Electromagnetic interference (EMI) shielding materials are disclosed in U.S. Pat. Nos. 4,935,296 and 5,089,326. The '296 patent discloses a composite containing an EMI shieldingly effective amount of metal-coated fibers, and details of such fibers can be found in U.S. Pat. Nos. 4,738,896; 4,759,950; 4,789,563 and 4,839,402. Radar absorptive coating materials are disclosed in U.S. Pat. Nos. 3,599,210 and 3,843,593. The '210 patent describes a coating containing fibers cut to a length of one-half wavelength of the anticipated radar frequency with the fibers being insulated along their lengths by thinly bonding a dielectric material such as epoxy, resin or varnish. The fibers are randomly dispersed within a solid matrix of resinous material.
U.S. Pat. No. 4,983,456 discloses electrically conductive laminates, conductive coatings, conductive adhesives, conductive inks, conductive gaskets and conductive caulking and sealing compounds wherein metal coated fibers are utilized. The fibers include a semi-metallic core made of carbon, boron or silicon-carbide and an electrically and/or thermally conductive layer of at least one electro-depositable metal.
U.S. Pat. No. 4,474,685 discloses high performance molding compounds for shielding electromagnetic interference. The patent describes electrically conductive bulk, granular or nodular molding compounds comprising a multi-component filler system of particulate carbon black, graphite and metal particles.
U.S. Pat. No. 4,360,440 discloses a method of spraying a composite of adhesive and fiber onto a wall or ceiling. The adhesive exhibits increased fire-retardancy, flame resistancy and thickness capability.
U.S. Pat. No. 4,534,998 discloses a coating process whereby an electrically conductive coating comprising carbon black, a wetting agent, and resin are sprayed onto a honeycomb structure in order to reduce the charging of a dielectric surface with potential gradients.
There is a need in the art for an EMI shielding material which provides flexibility of application. Further, it would be a significant advance in the art to provide a cost-effective method of applying an electromagnetic interference attenuating coating on a substrate to provide an EMI shielding member while imposing little impact on cost, weight or structural volume of a structure to which the shielding member is applied.